1. Field of the Invention
The present invention relates generally to improvements in a radiant-type heating system, and more particularly to a tubular insert which may be inserted into a heat-radiating tube to insulate the tube marginal portion from the immediate heat of a flame, directed into the tube from an open end thereof, to preheat air delivered to oxidize the flame tip, and to reduce the heat gradient along the operative tube length.
2. Description of the Prior Art
In radiant heating systems of the general type disclosed in U.S. Pat. No. 3,310,047, a flame is directed into an open end of an elongated tube. When so heated, the operative length of the tube emits usable infrared radiation which is appropriately directed toward the desired space or object to be heated.
However, several problems accompany the use of such heating systems. First, it is difficult to heat the tube to a uniform temperature along its entire operating length because the heat source is arranged at one end. In other words, by providing the flame at one end of the tube, an undesirable heat gradiant tends to develop along the tube. Otherwise stated, the tube is normally hotter proximate the flame than it is at a remote location. Of course, it is generally desired to heat the tube uniformly along its length.
Another problem is the difficulty in completely oxidizing the flame so as to reduce hydrocarbons in the fuel to carbon dioxide and water.